Crash in replaceAction (discord)

[qaisjp]

Describe the bug
replaceAction checks if a string has the prefix _ and the suffix _. A string of length 1, "_", passes this check.

To Reproduce
Steps to reproduce the behavior, on Discord type this:

1. /me hello
2. Click on "Edit message"
3. Change _hello_ to just _
4. panic

Expected behavior

No panic

Screenshots/debug logs

panic: runtime error: slice bounds out of range [1:0]

goroutine 206785 [running]:
github.com/42wim/matterbridge/bridge/discord.(*Bdiscord).replaceAction(...)
        /home/qaisjp/apps/matterbridge/bridge/discord/helpers.go:192
github.com/42wim/matterbridge/bridge/discord.(*Bdiscord).messageCreate(0xc000409110, 0xc0004d28c0, 0xc0024db7e0)
        /home/qaisjp/apps/matterbridge/bridge/discord/handlers.go:122 +0xbe5
github.com/matterbridge/discordgo.messageCreateEventHandler.Handle(0xc0005bc000, 0xc0004d28c0, 0x1841320, 0xc0024db7e0)
        /home/qaisjp/apps/matterbridge/vendor/github.com/matterbridge/discordgo/eventhandlers.go:497 +0x57
created by github.com/matterbridge/discordgo.(*Session).handle
        /home/qaisjp/apps/matterbridge/vendor/github.com/matterbridge/discordgo/event.go:171 +0x10e

Environment (please complete the following information):
Version based on 1.17.1, with some PRs cherry-picked. But replaceAction hasn't changed in months.

linux

Additional context
Line 191 needs length check to fix this

matterbridge/bridge/discord/helpers.go

Lines 190 to 195 in a18cb74

	func (b *Bdiscord) replaceAction(text string) (string, bool) {
	if strings.HasPrefix(text, "_") && strings.HasSuffix(text, "_") {
	return text[1 : len(text)-1], true
	}
	return text, false
	}